Since the passage of the Clean Water Act many industries have been required to institute treatment programs for the waste-water they generate before these waters are discharged into public drains and waterways. These programs often include on-site waste-water treatment processes, discharge into public treatment works or both.
Waste-water typically contains a wide variety of contaminants which must be removed prior to discharge of the waste-water into public waterways, such contaminants include: organic matter, such as proteins, carbohydrates and lipids; chemicals, such as pesticides, insecticides, heavy metals and fertilizers; and sewage. The waste-water is typically assessed in terms of its biochemical oxygen demand (BOD), total suspended solids (TSS) and dissolved oxygen (DO).
A number of processes have been developed which are directed at specific contaminants, for example: phenol oxidases and hydrogen peroxide have been used to decolorize pulp and paper mill waste-water (U.S. Pat. No. 5,407,577); enzymes from an atypical strain of Bacillus stearothermophilus have been used to degrade algal cell walls (U.S. Pat. No. 5,139,945); a combination of bacteria and enzymes have been used to improve the water quality of standing bodies of water (U.S. Pat. No. 5,227,067); cellulases have been used to digest wood/paper compositions (U.S. Pat. No. 5,326,477); Xanthomonas maltophilia and Bacillus thuringiensis have been used to degrade polar organic solvents (U.S. Pat. No. 5,369,031); yeast have been used to digest carbohydrate-containing waste-water (U.S. Pat. No. 5,075,008); a combination of .beta.-glucanase, (.alpha.-amylase and proteases have been used to digest microbial slime (U.S. Pat. No. 5,071,765); and a combination of amylase, lipase and/or proteases have been used to digest colloidal material such as starch, grease, fat and protein (U.S. Pat. No. 5,882,059). However, each of these compositions are directed at only a specific contaminant and they do not address the variety of contaminants which are usually found in waste-water and polluted water. A composition described in U.S. Pat. No. 3,635,797 used a yeast fermentation composition to deodorize sewage ponds and degrade organic waste. However, this composition has been found to be unstable and yielded variable results from one batch to another.
It is desirable to provide a composition and method for the digestion and decontamination of a variety of pollutants which are typically found in waste-water.